51.   There is also talk among some pilots of depressurizing the cabin as a defensive tactic, which reduces the oxygen levels and renders passengers and terrorists sleepy and befuddled.

52.   This instrument measures oxygen levels in the blood.

53.   When these same receptors detect low oxygen levels during sleep, they delay sending a message to the brain stem and the heart patient stops breathing.

54.   When lobster captains complained this summer of small catches, many attributed the problem to poor oxygen levels.

55.   When oxygen levels are high, hemoglobin narrows the arteries, slowing the flow of blood.

56.   Workers on the scene can also measure oxygen levels faster than in years past.

57.   A cable connects it to a monitor where doctors read the oxygen levels.

58.   A sensor that monitors oxygen level and combustion in the engine is placed on either side of the catalyst, the paper said.

59.   But the proper oxygen level of a fetus was something of a mystery, and there have been no devices that could try to measure it.

60.   Cahoon said Cape Fear never experienced plummeting oxygen levels because of its rapid water flow.